Attraction of Culex pipiens pallens (Diptera: Culicidae) to Floret Volatiles and Synthetic Blends of Its Nectar Host Plant Abelia chinensis (Rubiales: Caprifoliaceae).

Abelia chinensis R. Br. (Dipsacales: Caprifoliaceae) is one of the preferred nectar host plants for Culex pipiens pallens Coquillett (Diptera: Culicidae). However, the volatile compounds of its flowers that might be involved in directing mosquitoes' orientation to its nectaries remain unknown. In the present study, the volatile compounds released by A. chinensis florets were collected by solid phase microextraction fiber and analyzed by gas chromatography-mass spectrometry system. Based on the major component species in the volatile profile, a synthetic phytochemical blend (Blend B, composed of six compounds at their most attractive concentrations) was formulated, and its attractiveness was tested against the pentane extract of A. chinensis florets at most attractive concentration (Blend A) and a formerly developed synthetic phytochemical blend (Blend C) in the olfactometer, respectively. The results revealed that the volatile profile of A. chinensis florets was mainly composed of aromatic compounds, most of which had been reported to be attractive to other mosquito species. The synthetic Blend B was as attractive as Blend A (10-1-fold of the crude pentane extract) in the olfactometer bioassays, but they were not as attractive as the formerly developed Blend C. The present study indicated that quantitative and qualitative differences in the constituents of phytochemical blends could significantly affect their attractiveness to Cx. pipiens pallens, and the capture efficiency of phytochemical attractants deserves further research before being applied in the field.